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Difficulty: MediumSpecific Detail Inferences

The evolutionary mechanism underlying the development of aposematism—conspicuous warning coloration—in dendrobatid frogs has long provoked debate among evolutionary biologists. Aposematism presents a classic evolutionary paradox: a brightly colored mutant emerging within a cryptic (camouflaged) population should theoretically suffer heightened predation due to its increased visibility, presumably eliminating the trait before it can proliferate. To resolve this, traditional models posited a "kin selection" hypothesis, suggesting that while the initial brightly colored mutant is inevitably consumed, the predator subsequently avoids similar-looking individuals, thereby providing a survival advantage to the mutant's close relatives who share the nascent coloration gene.

However, recent phylogenetic analyses mapping the evolutionary history of the Dendrobatidae family demonstrate that toxicity evolved significantly earlier than conspicuous coloration. These findings lend support to an alternative "dietary specialization" hypothesis. According to this model, ancestral cryptic frogs first developed the physiological capacity to sequester alkaloid toxins from a specialized diet of alkaloid-rich ants and mites. Once these cryptic frogs became unpalatable, the selective pressure against visibility relaxed. This relaxation allowed for the gradual accumulation of mutations conferring bright coloration. The bright coloration eventually proved highly advantageous because it provided a more memorable visual cue to predators who had already learned to avoid the toxic, albeit cryptic, ancestors. Crucially, this model implies that predators are entirely capable of learning to associate unpalatability with specific prey even in the absence of conspicuous warning colors, although aposematism vastly enhances the speed and long-term retention of this learned avoidance.

Based on the passage, which one of the following can be most reasonably inferred about the predators of dendrobatid frogs?

  1. They possess the capacity to learn to recognize and avoid unpalatable prey that completely lack conspicuous warning coloration.Answer
  2. B
    They will completely cease predation on a frog population once they have consumed a single toxic, brightly colored mutant.
  3. C
    According to traditional evolutionary models, they first learn to avoid cryptic frogs before subsequently learning to avoid brightly colored ones.
  4. D
    They gradually accumulate a learned avoidance of brightly colored frogs that rely on a specialized diet of ants and mites.
  5. E
    Their ability to retain long-term avoidance of toxic prey depends primarily on the specific type of alkaloid sequestered by the frogs.

Answer

The correct answer is the option stating that predators possess the capacity to learn to recognize and avoid unpalatable prey that completely lack conspicuous warning coloration.
The correct answer accurately reflects a direct inference from the passage. The final paragraph explicitly states that under the dietary specialization hypothesis, bright coloration proved advantageous because it provided a visual cue to predators who 'had already learned to avoid the toxic, albeit cryptic, ancestors.' The author further clarifies that this model implies predators are 'entirely capable of learning to associate unpalatability with specific prey even in the absence of conspicuous warning colors.' Therefore, we can safely infer that the predators possess this cognitive capacity regarding camouflaged prey.

Step-by-Step Solution

1
Analyze the question stem to determine the task.
The task is to infer a specific detail about the predators of dendrobatid frogs based on the information provided in the passage.
Understanding the specific constraints of the question ensures that the selected answer will be a direct inference drawn from the text, rather than a broad summary or an unsupported assumption.
2
Locate the portions of the passage that discuss the capabilities and behaviors of the predators.
The first paragraph mentions predators consuming initial mutants under the kin selection hypothesis. The second paragraph discusses predators learning to avoid toxic ancestors and responding to visual cues.
Scanning the text for the relevant subject (predators) isolates the evidence needed to evaluate the options.
3
Evaluate the specific claims made about predators in the second paragraph.
The text states that bright coloration provided a visual cue to predators who 'had already learned to avoid the toxic, albeit cryptic, ancestors' and explicitly notes that predators are capable of learning this 'even in the absence of conspicuous warning colors.'
Careful reading of the targeted sentences reveals the exact parameters of what the author implies about predator capabilities.
4
Match the textual evidence against the given options.
The correct option perfectly aligns with the passage's concluding point that predators can learn to associate toxicity with prey without bright warning colors.
Validating the correct inference guarantees that the answer does not overstate certainty or misattribute a viewpoint.

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Specific Detail Inferences
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